Phase shifting device



oct. 11, 1932. y

' W. A. KNooP PHASE SHIFTING DEVICE Filed April 18, 1931 /NVENTOP W. AKNOOP W ATTORNEY mmmm x Q tok 1C.

DEEE

m m Ummm Patented 0.111, 1932 f VUNITED "sTATEs lPAJLEN'FI OFFICE gyWILLIAM:l A. 'KNOOP, OF HEMISTEAD, NEW YORK, ASSIGNOR T0 BELL TELEPHONELABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK PHASE SHIFTING DEVICE This inventionrelates to a phase shiftingdevice for use in an vimpulse transmission systemV employingsynchronously rotating distributing devices. It is particularly usefulin high speed printing telegraph systems. An object ofthe invention isto facilitate the phase adjustment of synchronously driven rotarydistributing d-evices.

f 'A more specific object oti the invention is to establish proper phaserelation between a continuously rotating receiving impulse distributingdevice Vand incoming signal impulses. Y v

In high speed telegraph systems employing long loaded submarine cables,synchronism between rotary distributors at opposite ends of the cable ismaintained by utilizing signal impulsesto operate corrector circuits.

"320 These corrector circuits are arranged to correct thev distributorat the receiving end of the cable either by mechanical means, such' asdisclosed in G. A. Locke, U. S. Patent No. 1,670,461, issued May 22,1928, or by continu- Q5 ous electrical means, such as disclosed in U. S.Patent 1,848,180 granted to W. A. Knoop on March 8, y1982. Thecorrection thus effected in both disclosures is gradual and is highlydesirable when the receiving i) distributor is in approximate phase withthe incoming signals. However, at the. beginning of a transmissionperiod, particularly after a period of non-use, itmight be necessary toorient the receiving rings which are usually orientable with respect tothe other rings onv theV same distributor, through a considerable arc toobtain `an approximate phase relation with the incoming signals. Thelamount of orientation may be determined by means of a series of lampswhich may be temporarily connected to the receiving distributors asshown in A. M. Curtis Patent 1,689,828, issued October 30, 1928.

According to the present invention the phase relation between thereceiving dis- -tributor and the incoming signals is established in aneXpeditious and eiiicient manner by arranging intermediate the receivingdistributor and the printers or lamps a cornmutator device iXedlymounted on a rota- 1931. Serial No. 531,107.

table shaft. The shaft has also tixedly mounted thereon a series ofrings which are insulated from each other and the shaft. Each of therings is electrically connected in iixed relation to one segment or barof the l55 commutator. Individual brushes connect the segments of thereceiving distributor with the insulated rings and other individualbrushes connect the commutator bars with the phasing lamps or theselector magnets of the printers. In this way, connections through thecommutator may be varied at will by rotating the commutator in eitherdirection to change lthe positions of the H brushes with respect to thereceiving seg-* yments and lamps, thereby obtaining the desired phaserelation as indicated byV the lamps. A switch is provided fordisconnecting the lampsy and for connecting`the printers after the phaserelationV is obtained. Y"7'0 A better understanding of the inventionwill be had from the lfollowing detailed description and appendedVclaims when taken in conjunction with the accompanying, drawing ofwhich,

Fig. 1 shows a schematic circuit arrangement of the invention, and

Fig. 2 represents an assembly of the commutator adapted for use in Fig.1.

Like :reference characters represent like` arts. p Referring to Fig. 1signal impulses originating at a distant transmitting station Y areimpressed over a transmission line 12, onto aHAL continuous ring13 ofthe receiving distribu- "85 tor 14 at station X. The distributor 14comprises, in addition to continuous-ring 13, a segmented ring 15 and arotatable brush 16. The distributor shown provides for receiving signalsover four channels of transmission, but it is understood that thedistributor may be designed to provide for a greater or a lesser numberof chanrtels. Furthermore, the distributor provides to receive signalsiny accordance with the Baudot or tive-unit impulse code, although it isalso understood that the distributor is not to be limited to thisparticular code.

Inasmuch as the distributor shown in Fig. 100

Allis designed for four channels, the ring contains fort-y segments,that is, ten for each channel. Alternate segments are fixedly connectedto brushes 171and the remaining segments are left dead. Should the brush16 be ini, phase with the incoming signal impulses, it will be 'passingover-one of the segments connected to a brush 17 at the timey the.middle portionof agunitlength impulse is` impressed *o'njther ring.13.Y lThis phase relaj `tionis known inthe art-as the true'phase incontradistinction to the approximatephase which will be hereinafterdescribed. 'The segments connected to brushes 17 will be here- Y`inafter referred to as live segments.

Then 1t is-desired to transmitsignals, vpar- VVticularly aftera-periodof non-use, as forexample, at the beginning of a days' run, it isusually the practice, first,'to establish approximatephase between thedistributors at opposite ends of the transmission'line. Ac-

'cordingly, the receiving ring` set, such'as'ring set ll-,ismade-orientable with respect tothe 4may, be rotated at willineitherdirection by means-of -a hand-'knob 22, the amount of rotationYbeing indicated by' Vwheel 23 and pointer 24. FiXedly, butinsulatively,mount ed on shaft '19 and in parallel'V relation with.the.- commutator ringV 18 are twenty individual slip rings 25 which arerespectively y positioned in engagement with ybrushes 17. The commutatorring 18 is dividedinto twenltysegments'or bars to correspond tothenumber of slip Vrings and these bars are Vrespec- "tif-vely`connected in fixed relation tothe slip rings 'by means .of vconductors26 (.Fig. 1).

' yFixedly positioned in l.engageable' relation fwiththe twenty .bars ofcommutator ringV V18 lare'vtwenty 'brushes l27 which are fixedly, `but'insulati-*Vely* mounted lon some Apart of the base structure Y (notshown), supporting the standards 20'a'n'd 21. The brushes 27 arerespectively connected by conductors 28 to contacts 29 of gang switchbar30, which` is arranged to 'be operated rby hand' to connect. kryeithertheprinters 31, 32, 33 and 34, corre- :spending respectively Vto thefour channels, A lor the lamps '35v to the receiving circuit, the lamps35 serving to indicate the phase relaationbefore the printers areconnected.

remaining nineteen lamps. shown-herein, lamp 3"(V is selected to havethetransparent red cap, it being the third lamp in channel D. If the systemis insynchron- `ous` phase, then, during `each revolution of fbrush16,'red'lamp will light and the two :adjacent .lamps on `each side ofit, that' is, .the first, second, fourth and Vfifth lamps of Operationof the system In multiplex transmission systems, particularly wheretransmission is over a long subf marine cable, and wherein polar signalsare 'employed the polarity ofthe marking and spacing 'impulses arerreverse'dat the. end of each channel. When it is'desired to st art op-'eration after a period ofnon-use, phasing signals are transmittedby'each of the transmitters,"in1turn, at station Y. :These signals maybe constituted of various combinations of .impulses of positive and'negativeV polari-v ties. For the purpose of illustration, it isassumedthat lifnthe'first channel, say channel yA.,.the first, second,fourth-and iifthimpulses are of positive polarity andthe third impulseis negative; in the second channels, say channel. B, all the fiveimpulsesA are of negative polarity; in the third channel, say channelC,all the five impulsesare of positive polarity; and in thefourthchannel,Saychannel D, the first, second, Vfourth and lifthim'pulsesare ofnegative polarity-and thethi'rd impulse is of positive polarity. Thelamps 35 at station X are shown connected tothe negative pole ofgrounded battery 36.

If the receiving `distributor brush is, in synchronous phase with .theincoming signals, it will cause, yas it passes over each of the livesegments of ring 15, amomentary Qlightingof the first, second, fourthand fifth Y'lamps v'of clianne'lfA, all the five .lampsfof j'chann'el C,andthe third lamp of channel D. "The remaining lamps which' receive fromtheir respectively associated live7 segments,

impulses of negative polarity, will not light `beca-use of likepolarities atopposite ends oftheir circuits.

'Howevenfafter a period of n on-use, synchronous' phase as setforthabove, is rarely had, and therefore, it is necessary thatthe Y system beadjusted to establish what is known as approximate phase, before thetransmission of message signals begins. .This-is acl"complishedproviding one lamp withsome suitable means such as a transparent redcap, which will be easily "distinguished from the In the system channel'1), iwill not light. If this condition is not had, as is usually thecase, then the commutator 'ring 18 maybe rotated by turning knob 22 ineither direction until the desired .condition is obtained. i

The system `is then adjusted for truc synchronous phase, that is, vthecondition wherein the live segments are positioned'to :re-

ceive-the middle portion, respectively, ofthe.

kas

incoming impulses. This adjustment is made by orienting the ring set 14,as is well known in the art, through a small arc. The range oforientation required is at the most a little more than the length of afull signal impulse. In a four-channel system, such as shown herein,this range would be a little more than 18, say, 27 or 30. This allowsthe exact positioning of the receiving segment with respect to theincoming signals without moving the ring set 14 through such a range asto break the leads.

The purpose of the true phase adjustment may be better understood byreferring to the segment of channel D' shown on ring 15. I-Iere areshown in dotted lines three possible positions of the incoming impulsewith respect to the third live segment of the channel, which may beobtained by the approximate phasing adjustment. The impulse in its eX-treme left-hand position which is designated a, is received partly onthe second and the third live segments, the middle or effective portionbeing received on the dead segments between them. However, the portionreceived on the third segment may be of sufficient strength to causelamp 37 to flash. Then again the impulse may be received in its extremeright-hand position, designated b, wherein the impulse is distributedover the third and fourth live segments and the dead segments betweenthem. In either of these positions there might be suicient portions ofthe impulse received on the third segment to cause lamp 37 to flash.Therefore it is necessary that a further adjustment be made to shift thering set 14 sufficiently in one or the other direction until the impulseis received in the position designated c, wherein the middle portion isreceived wholly on the third live segment. The means for making the lastmentioned adjustment is well known in the art. It is therefore seen thatthe adjustment for true vsynchronous phase is limited to an angulardistance of a little more than 18 for a four-channel system.

-What is claimed is:

1. In an impulse transmission system, a phase shifting device comprisingindividual means for receiving individual impulses, elements forindicating indivdual impulses, and manually operated means electricallyconnected intermediate said individual means and said elements, arrangedto change the connection of each of the individual means from one ofsaid elements to another.

2. In an impulse transmission system comprising means for receivingimpulses over a plurality of channels, a plurality of means forrespectively recording groups of impulses received over said pluralityof channels, means for indicating the phase relation between incomingimpulses and said recording l means, normally stationary meansinterconnecting said receiving means and said indil eating meanscomprising a circuit interlchanger arranged to be manually rotated toobtain any desired phase relation between the received impulses and saidindicating means, and means for connecting to said receiving means thesaid recording means, in place of said indicatin means, when the desiredphase relation 1s obtained.

3. In an impulse transmission system, according to claim 2, wherein thenormally stationary means is a rotatable commutator device comprising ashaft, a ring constituted of insulated segments and fixedly mounted onsaid shaft, a plurality of insulated slip rings arranged in parallel tosaid segmented ring and fiXedly mounted on said shaft, individualelectrical connections between said slip rings and said segments, andstationary brushes arranged in engageable relation with each of saidslip rings and said segments.

4. In an impulse transmission system according to claim 2, wherein anindicator is provided on said normally stationary means for indicatingthe amount of rotation given thereto to establish the desired phaserelation.

5. In an impulse transmission system, a

hasel shifting device comprising a distributing device for receivingline impulses, individual means for indicating said received impulses, arotatable shaft having insulatively mounted thereon and insulated fromeach other a plurality of members in engagement with a plurality ofelements, respectively, on said distributing device, a seconddistributing device ixedly mounted on said shaft, a plurality of contactelements insulatively mounted on said second distributing device andelectrically connected in fixed relation to said plurality of members,respectively, and a plurality of elements for maintaining each of saidcontact elements in connection with one of said indicating lamps, saidshaft being rotatable in either direction to change the connectionsbetween said contact elements and said indicating means as desired.

In Witness whereof, I hereunto subscribe my name this 15th day of April,1931.

WILLIAM A. KNOOP.

